I'd like to see a section (or just a paragraph) in the RFC summarizing
the benefits of making this change. Right now the introduction says
that using dynamic properties in modern code "is rarely done
intentionally" implying that it's typically done unintentionally,
however I can't remember the last time I saw unintentional use either.
Is this a common cause of bugs? The internal impact section mentions
saving 8 bytes per object plus an unspecified "dramatic" amount for an
object iterated over via `foreach` which sounds nice but leaves me
guesstimating at real-world impact.
I don't much care for dynamic properties, but I also don't much see
them outside legacy code so they're not bringing me troubles either.
Breaking working code, however, would.